Apocrine Hidrocystoma with IgG4 Plasma Cell Infiltration Presenting as Recurrent Chalazion: A Case Report.

Apocrine hidrocystomas are benign cystic tumors resulting from apocrine sweat glands' proliferation. They typically present as solitary, slow-growing nodules at the head and neck, especially in the periorbital cutaneous region. We present a case of periorbital apocrine hidrocystoma in a 22-year-old woman that was treated as chalazion previously. Besides the hallmark histopathological findings of apocrine hidrocystoma, IgG4 plasma cell infiltration of the cystic wall was also found. The ratio of IgG4-to-IgG-positive plasma cells was high, whereas serum IgG4 was within the standard limit. This is, to date, the only probable IgG4-related ophthalmic disease associated with apocrine hidrocystoma.